New York, Aug 29 (TIWN) A key amino-acid mutation in the SARS-CoV-2 spike protein might explain why the Delta variant of Covid-19 has spread so swiftly across the world, say researchers.

SARS-CoV-2 Delta variant has rapidly replaced the Alpha variant around the world. According to epidemiological studies, the Delta variant, first identified in India in late 2020, is at least 40 percent more transmissible than the Alpha variant, first identified in the UK, last year.  However, the mechanism that drives this global replacement has not been defined yet.  The study, yet to be peer-reviewed and posted on pre-print server bioRxiv, showed how P681R mutation in the Delta spike plays a key role in the replacement of the Alpha-to-Delta variant.  "Delta SARS-CoV-2 efficiently outcompeted the Alpha variant in human lung epithelial cells and primary human airway tissues," wrote researchers from the University of Texas and others in the abstract.  The P681R mutation falls within an intensely studied region of the spike protein called the furin cleavage site, Nature reported.  The short string of amino acids P681R is associated with heightened infectivity in other viruses such as influenza. However, it has not previously been found in sarbecoviruses -- the family of coronaviruses to which SARS-CoV-2 belongs.